Peter Marris, who has died aged 79, was a creatively original sociologist who did extensive fieldwork in Britain, Africa and the United States. His research - in Bethnal Green, Lagos, Nairobi, New York and Los Angeles - spanned rich and poor in both industrialised and developing countries. He witnessed human loss of different kinds, and in beautiful prose captured again and again what are the individual and social ramifications of "loss and change" - a theme that became the title of one of his later books.

Born in London, Peter attended Bryanston school, in Blandford, Dorset, an experience he said introduced him early to the pain of family separation. His national service was spent as an RAF translator in postwar Japan, shortly after the obliteration of Hiroshima and Nagasaki. We met in 1948 at Cambridge (he was at Clare College), where we read philosophy and psychology, sitting at the feet of Bertrand Russell, John Wisdom and Frederick Bartlett. He had already written a remarkable novel about Japan, but the publisher went bust. After finishing his degree, he joined the Colonial Service for two years as a district officer in Kenya.

Peter wrote a chapter about those years in Norman Mackenzie's Conviction (1958), entitled Accessory After the Fact. While his back was turned, a policeman had pumped bullets into an unarmed schoolboy only a yard away who was wearing a Boy Scout's belt. It was a crime, but Peter felt unable to act.

In his magnanimous and selfless piece about colonial policy, he remarked that "in spite of the gross obscenities and outrageous cruelty of the Mau Mau rebellion, it compelled the sympathy of the Kikuyu people: it was, at last, something of their own, through which they could recover their respect for themselves ... It overcame their repugnance for the arbitrary terrorism of which they were themselves the victims. Good government is no substitute for self-government, especially since good government ends by using the methods which are used against it."

In 1955 Peter was persuaded to join Michael Young (obituary, January 16 2002), Peter Willmott (obituary, April 19 2000) and myself at the Institute of Community Studies in Bethnal Green. He stayed until 1972, and after contributing interviews to my book The Family Life of Old People (1957) became the most prolific - and international - of the small group of sociological devotees at the institute. Between 1958 and 1972 he published five books, the first being Widows and their Families (1958), a tender account of grief and mourning, and the first book in the UK on the subject of widowhood.

He wrote: "For a while, she may become indifferent even to the care of her children: her home, her future, her family - nothing matters any more. Bewildered by her loss, she cannot at first believe it. She still hears his footsteps on the stairs, his voice calling, finds herself waiting for him when the men come home, and as each habitual expectation is unfulfilled, she begins to realise the meaning of his death ..."

In 1958-59 Peter went back to Africa. In Family and Social Change in an African City (1961), he reported his interviews with families cleared from Lagos slums. He found that they had suffered acutely from bad planning and bungled rehousing. Many had been deprived of relatively secure work and social connections, and hundreds of plots from which families had been cleared remained unbuilt.

From 1966 to 1968 he overcame his early experiences in Kenya by going back to prepare and publish, with Anthony Somerset, African Businessmen (1971), a positive study of entrepreneurs and development. They interviewed a total of 1,271 figures in commerce and industry, some of whom had been awarded government loans. The worst problems were found to be overburdened management, conflicting loyalties, untrustworthy and demanding relatives, and social isolation.

In the years between these Africa books, Peter wrote The Experience of Higher Education (1964), a personal reflection on the ideals and purposes of higher education based on survey research in Cambridge, Leeds and Southampton universities and Northampton College of Advanced Technology. With Martin Rein, he wrote Dilemmas of Social Reform (1967), a demolition of the hopes raised by a range of community action projects designed to help the US poor. He and Rein visited 12 projects in different American cities. The launch of President Lyndon Johnson's war on poverty in 1964 had been beset by the contradictions of entrenched political and corporate interests, and the book set the scene for eventual disillusion with that war, despite small gains for some groups among the poorest fifth of the population.

From 1972 to 1976 Peter worked at the Centre for Environmental Studies, in London, but by the mid-1970s he took an increasing number of opportunities to visit the US. In 1976, he became professor in the school of architecture and urban planning in the University of California, Los Angeles, remaining there until 1991. It was a settled, happy and productive period. He married Dolores Hayden, now of Yale University, and became an US citizen. He published Loss and Change (1974), and lectured extensively on its themes of conservatism and innovation. He taught in the sociology department at Yale until 2004.

In Meaning and Action (1987), an expanded version of his earlier work, Community Planning and Conceptions of Change and the Politics of Uncertainty (1982), Peter extended psychiatric and psychological theories about individuals to the motives of national and international organisations and governments - an idea still rare in economic and social analysis. He wrote a fine novel, The Dreams of General Jerusalem (1988), about the interweaving of power, idealism and ambition in a new African nation and the forlorn ideas of American philanthropists anxious to leave their mark there. Conscious of human frailties, he invested all his prose with finely expressed insights that linger in the memory. In The P olitics of Uncertainty (1996) he wrote that personal attachments were the root of truly social security, "a more hopeful politics of collaboration and reciprocity".

He is survived by Dolores, his daughter Laura and his younger brother Tyrell.

· Peter Horsey Marris, sociologist, born July 6 1927; died June 25 2007

· This article was amended on Tuesday July 10 2007. The sociologist Peter Marris worked for the Centre for Environmental Studies in London in the 1970s and not, as the editing had it, for the unrelated organisation of the same name in Loughborough, which started life in 1999. This has been corrected.